a specific procedure for pilot task sharing. It involves one pilot flying (or managing) the aircraft on approach exclusively ‘head down’ by reference to the flight instruments whilst the other monitors.
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Not later than the approach of the applicable DA/DH or MDA/MDH, the monitoring pilot seeks visual external references so that when the ‘head-down’ pilot calls “Decide”, they are in a position to make a prompt and unequivocal call of either call “Land” or "Go-Around". If the call is “Go Around”, the head-down pilot flies the prescribed or ad hoc cleared Missed Approach and the monitoring pilot continues in that role. If the call is “Land”, the pilot who has been monitoring and has made that call takes over as PF and continues to the landing. If visual reference should be lost below DA/MDA then the pilot who has taken over as PF must commence the go around before handing over to the other pilot at a suitable point during the climb-out.
The monitored approach has sometimes been described as a “delegated” approach compared to the description of the traditional approach, where the both a landing and a go around are flown by the pilot who made the approach, which has been called an “assisted” approach. (same source)